Selective fuse plug shell



Nov. 8, 1932. H. J. l.. FRANK sELEcTIvE FUSE PLUG SHELL Filed Feb. 14,195o 3 sheetsheez 1 INVENTOR ATTORM Nov. 8, 1932. H. J, FRANK 1,887,089

SELECTIVE FUSE PLUG SHELL Filed Feb. 14. 1930 3 Sheets-Sheet 2 ez l 6/7f/.f g x i i ii j INVENToR ATTORNEY Nov. 8, 1932. H. J. L. FRANK1,887,089

sELEcTrvE FusE PLUG SHELL Filedfeb. 14. 1930 s sheets-sheet s INVENTORATTORNEY YPatented Nov. 8, 1932 UNITED STATES.

PATENT OFFICE HABBISQ'H J, L. FRANK, 0F HIGHLAND PARK, MICHIGAN,ASSIGNOB TO BULL DOG ELECTRl- PRODUCTS COMPANY, 0F HAMTBAMCX, MICHIGAN,.A CORPORATION OF WEST VIRGXNIA SELECTIVE FUSE PLUG SHELL .plicnton MedFebruary 14, 133D. Serial No, 428,231.

etes to current take o is 'plug which may he 1 accommodate cartridge sengths and capacities.

Another object is e plug having a. use consealing shell which may bemoved to expose one and only one7 ci the fuses, at any one time, wherebythe exposed fuse may be removed and replaced Without disassembling thedevice, even in part.

A further object is a plug of the tye de-i scribed in the foregoingparagraph, w erein the shell is so interlocked with the receptacle withwhich it cooperates that movement of the shell for fuse exposure, is notpossible unless and until the plug has been Withdrawn from the livereceptacle, this feature preventing fuse manipulation whilethe fuse isaliveu L further object is a plug having grounding means whieh eectivelygrounds the plug to the distribution conduit, before the plug can beplugged into the receptacle7 until after i the the plug is Withdrawnfrom the receptacle,

i and all the While the plug is plugged in the receptacle.

A further object is a plug which has projecting contactsy readilyconvertible from the knife blade or male type, to the parallel leaf orfemale type.

further object is a plug made of a numloer of stock parts, assembled asdesired, to create plugs of dilerent capacities.

. A further object is a plug having parts designed to afford maximumelectrical insulation consistent with compactness.

Still further objects will readily occur to those skilled in the artupon reference to the following description and the accompanyingdrawings in which 'to Figs l and S7 it seen that the plug includes twocomplementary insulating por tions l@ and ils between which the fusesare disposed and from one oi which project the plug contacts, and to theother of which the current conductors are connected.

The portion i0 is made of molded insulation, such as a phenoliccondensation product, and is molded around the contacts i2. Projectingdown from its lower face, Figs. 4 and 6, is a central section 13 oi 'l'contour', and from each outer point of the T, barriers le projectradially to denne peripherally spaced recesses l5, these containing endsof the contirets-l2.

Each or the ends is provided with a thread ed hole i6 into which may bethreaded a screw 17 for securing a cartridge usevclip i8 to the Contact,the construction aording remorn ability to the fuse clips.

The portion il, complementary to the portion l0, is also made of moldedinsulation anf is molded around the connecting lugs 21, these havingbinding posts 22 to which may be conn nected ends o conductor 23,leading to a ma chine or other current consuming device.

Ill

' will serve to close electrical lines from contacts 12 to lugs 21 andconductors 23, and it will be seen that the electrical lines arerelatively insulated by the complementary barriers 14 and 25.

Thevplug enclosure and details The portions 10 and 11, together withtheir fuses, clips etc. are enclosed in a hollow cylindrical shell 32 ofinsulation, the same being capped at the plug contactv end by a ringshaped annularly grooved casting' 33 and at the cable end by a platecasting 34 thru which the conductors 23 pass. The shell. 32 is rotatablebetween the castings and around the portions 10 and 11 and is providedwith an opening 35 (Fig. 6) adapted to be registered with a selected oneof the recesses, as desired, or with none of them, as desired. Thecasting 33 is provided with a friction leaf spring 36 (Fig. 4) to engagethe shell, thereby restraining its rotation, although not absolutelypreventing rotation.

If desired, a knob 37 on the leaf may be provided to engage in adepression in the shell, the engagement alining the shell with thecasting, so that the shell opening is normally in registry with one ofthe barriers 14-25.

Although the fuses 30 tend to hold portions 10 and 11 to each other, inthe shell, other and more reliable means may be provided, if desired, toattain this result, and such means are shown best in Fig. 3. The meansincludes long bolts 38 passed thru .the portions and threaded at oneend, into lugs 39 on the casting 33, and at the other end, provided withnuts, one of which 40 holds the portions 10 and 11 together, and theother of which 41 holds the casting 34 in place. The bolts pass thru thebarriers .14-25 on the portions 10 and 11, and are surrounded byinsulating tubes 42, which not only insulate the bolts from the spacesbetween the portions, but also serve to space the portions l0 and 11 at/desired distances.

It will be observed that the length of the vertical space between theportions, and consequently the length of the shell 32, the bolts 38, andthe tubes 42, depends upon the length of the fuses 30. Accordingly, whenthe plug is to accommodate low voltage or short fuses, short ones of theparts above mentioned will be chosen, but'when'the plug is to be usedfor` high voltage or with long fuses, long ones of the parts will beselected. It will' further be seen that to change a plug fromonelength'to another, is a veryV simple matter, only certain,inexpensive, parts being substituted.

It will also be observed that plugs of large current carrying capacitywill beprovided with large fuse clips easily mounted in the taperedrecesses 154-26, whereas lower amperage plugs will contain smaller fuseclips.'V`

ccordingly, the creation and reconstruction of plugs, for variouselectrical demands, is a simple and inexpensive matter.

In order to isolate respective contacts 12 and respective binding posts22, and to reduce creepage, etc., barriers are formed on the top surfaceof the portion 10 (Fig. 2) and barriers 46 are formed on the bottomsurface of the portion 11 (Fig. 7). Contacts l2 are further isolatedfrom each other, when live, by the walls 47 between the various outletoles 48 on the outlet block 49 (Fig. 4) of the uct.

Further, while contacts 12 are shown as being of the blade or make type,to cooperate.

with leaf or female contacts 50 in the outlet block 49, they might wellbe of the leaf or female type, to cooperate with bare bus bars or withblade or male contacts, accessible thru or in the block.

It will be observed that one set of the barriers, 14-25 namely the oneforming the legs of the T (Fig.'6) is extended peripherally so as to beof greater arcuate length than the opening 35 in the shell.` Further,this barrier is provided with recesses 56 in which are seated nuts 57thru which pass screws 58 for holding an arcuate insulating plate 59against the barriers. The plate 59 bridges the space isters with-theplate 59. The latter may bemade of a different color than the portionsl0 and 11 so as to indicate its location by color contrast, and is madeof the same colorA as the shell so as to make the plugin normal use,more attractive than would otherwise be the case. Y

The mounting, polm'iez'ng, interlocking and grounding details In priorart plug devices, the' friction and spring pressure between the plug andreceptaclev contacts is relied upon to maintain the plug and receptaclein conjunction. This practice is perhaps satisfactory, in some cases,but is not as reliable as might be desired. Accordingly, plug mountingmeans, which may be dispensed with, if desired, have been disclosed andthe same will now be described, in connection with parts provided on theduct.

The lduct 60 is provided on its lower surface with an opening aroundwhich is mounted a centrally apertured outlet plate 61, the

' latter having headed pins 62 passing upwardly-thru slots 63 inparallel locking plates 64, there being coiled springs 65 for pressingthe locking plates against the plate 61. The out? let plate, further hasholes 66 in registry.

with vlocking plate keyhole slots 67, these.

holes' and slots receiving the headed pins 68` on the plug ring casting33. Wien the plug is plugged into the receptacle 49, the plug pins 68pass thru the holes 66 and the large parts of the keyholer slots 67,after which the locking plates are shifted to cause the small parts ofthe keyhole slots 67 to line up with the holes 66, thus locking the plugto the outlet plate.

prevent access to lier use renewal 'lor when the plug is v interlockmeans, i such qm un en the plug is g i he duct outlet, however, and islive, tue plunger 1s retract-ed and the i in 'il is disposed in the slotl5, preventing the shell from being rotated. Furtner. tue 'lfv'n il n iMm" w slo.-J lo, shell opening ou plunge; l() aie so located withrespect to each other, that -the slot 73 must be in line with plungerpin 7l, and opening 35 must be in registry with insulating plate 59,before the plunger can be retracted to permit pluggingin ofthe plug.Accordingly, it is impossible to plug-in While any fuse or line in theplug "is exposed.

Further, the plunger 70 projects beyond the contacts l2, and musttherefore be retracted by its engagement with the duct bcfore thecontacts l2 can malle with the outlet contacts 50. Accordingly, the plugenclosure is grounded to the grounded duct before Athe plug is madelive. As a corollary, the plug enclosure is grounded to the duct all thewhile the plug is live., and even shortly after the plug is pulled outof the receptacle.

60 It will iurther be noted that upper casting 33 completelyT closes thereceptacle opening when the plug is in circuit, thus sealing the liveparts of the plug in the plug shell and the duct.

l Now having described the invention and The outlet plate and receptacleas a unit,

' scctioi the preferred embodiment thereof, it is to be understood thatthe said invention is to be limited, not to the specific details hereinset forth but only by the scope of the claims which follow.

What I claim is:

l. In a fused plug adapted for operative connection with a bus barstructure a central space-enclosing cap provided with means fordetachably engagin the bus har structure, thereby to hold the plug inplace,

a peripherally recessed, intermediate section oi' insulating material,pairs of relatively spaced Contact members in 'recesses of saidintermediate section, each e ed with a fuse clip, one of eati contactmembers acted at one enc, the other one o" tact members g plug' contactwhich project rounded enclosed by s f `cap, longitudine ing the partsrotate ly mounted rial surrounding said and .Xie-ving aperto? tercdTenth selected one o Lize .ecesses said intermediate section to ithereto *for inspection or replacement of fuse 'therein positioned.,

:2. n a fused plug, a pair o 'rininal caps, one oi' which is provided speripheral flange de.,A lng a central protective recess and withperiplierally disposed for detachably engaging parts -of a bus barstructure, means for oetacliably holding said caps in l deslred spacedrelation, an intermediate member of insulating inaleriai having aplurality of peripherally spaced and peripherally accessible recesseswherein fuses may be positioned in isolation from one another, a pair ofspaced' fuse clips positioned in each of said recesses, one of saidclips being provided with a binding post positioned at one end of saidintermediate member, the other of said clips being provided with a plugcontact which projects into and is surrounded by the 'peripheral liangeof the adjacent one of said caps, and a rotatably mounted insulatingshell surrounding said intermediate member and Aadapted to protect saidfuseliousing recesses from external access, said shell having anaperture adapted to he moved into registry with selected ones of saidrecesses as the shell is rotated.

3. In a fused ico plug, a. peripheral body of L insulating' materialhaving peripheral re'- vided with a fuse clip, one of each pair ofterminal members having its end contoured to binding post form, the endof its companion member projecting from the opposite end of saidinsulating body and formed as a plug contact,terminal plates positionedat the ends of and secured to said body'of insulating material, that oneof said plates adjacent said projecting plug contacts having aperipheral skirting which forms a protective recess into which said plugcontacts project, means appurtenant said last mentioned terminal platefor detachably connecting it and accordingly, the body to a bus barstructure and thereby effecting an electrical contact between saidprojecting plug contacts and the busl bar structure, and a rotatablymounted insulating shell surrounding said peripherally recessed body andadapted to protect the fuses positioned in the several recesses'againstexternal access, said shell having an aperlure adapted to be moved intoregistry with selected ones of said recesses as the shell is rotated.v

4. In a fused plug adapted for operative connection with a bus barstructure, a plate provided with means for detachably engaging the busbar structure, means for preventing the complete connection of said plugand bus bar structure until a` ground connection therebetween has firstbeen made, said plate also having a centrally located recessed portion,a peripherally recessed body of insulating material having one endengagihg said plate, a pair of circuit terminals spacedly disposed ineach of the recesses of said insulating body, one of each pair of saidterminals having end portions in the form of plug contacts which projectinto the central recess of said plate, the other of the terminals ineach recess projecting beyond the opposite end of said insulating body tprovide a conc luctor binding portion, a second plate forming a capover'the last mentioned end of the insulating body, a fuse clip carriedby each of said terminals in said recesses, and a rotatably mounted,insulating shell surround: mg said recessed insulating body and havingan aperture adapted to afford access to selected ones of said recessesand to the fuse positioned therein only when the shell is ro- .tated tosuch position that its aperture registers With the recess.

5. A fused plug comprising an intermediate insulating block providedwith a plurality of peripherally accessible recesses, a pair ofrelatively spaced fuse clips positioned 1n each of said recesses, eachpair being adapted to be connected by and/detachably support a fusepositioned in said recess, a protective frame for said block comprisingend plates and connecting rods, one of said plates being formedfor'detachable connection with a bus bar structure when properlypositioned thereon, and. a protective insulating shell rotatablypositioned about said insulating block and provided with an accessaperture Whereby access to any of said recesses is permitted only whenthe aperture is registered therewith, and plug terminals projecting fromone of each pair of fuse clips.

6.' Means for detachably and accessibly 'supporting a plurality of fusesin insulated and normally protected position, comprising al cylindricalblock of insulation having spaced peripherally accessible recesses, arotatably mounted protective shell surrounding the block and having anaperture thru which access to selected ones of said recesses ispermitted when the aperture is in registry therewith, a pair of spacedfuse clips positioned in each of said recesses, a plug contact extendingfrom one of each pair of clips beyond the end of said block, andstructurally connected protective plates positioned at the ends of saidblock, one of said plateshaving a skirt adaptf vthrough one end of saidbody, a frame for said body and its supported elements and forprotecting said plug contacts, means on said frame for detachablysecuring said plug in operative relation to current-carrying elements,and a shell rotatably supported by said frame to conceal said recesses,said shell having an aperture thru which may be had access to selectedones of said recesses, when the aperture is in registry with any onethereof.

8. In a fused plug, a frame provided with means for permitting thedetachable operative installation of the plug on a distribution system,an insulating body Within said frame and provided With peripherallyopening recesses, fuses in said recesses, a shell rotatably supported bysaid frame and surrounding said body, said shell having an apertureadapted to be registered With selected ones of said recesses and meansfor preventing rotative movement of said shell when the plug isconnected to said distribution system.

Q. In a fused plug, a pair of spaced end sections, each containing afuse clip, a fuse connecting and supported in said clips, cableconnection means on one of said sections and plug contacts on the other,and means comprising elongated rods removably positioned in the sectionsand connecting them for maintaining them in assembly, the rods beinginsulated from the space between the sections.

10. In a fused plug having an end section provided with plug contactsand an apertured, rotatable, fuse-concealing shell, means llO on the endsection for preventing rotation of the shell when the plug contacts arein engagement with cooperating contacts, the means also preventing theplug contacts from being engaged with cooperating contacts while theshell is not in fuseconcealing position.

11. Ina fused plug, spaced end sections of insulation havingperipherally accessible fuse containing recesses separated by radiallyextending barrier walls of insulation, a rotatable insulating shellsurrounding said end sections and having an aperture adapted to beregistered with selected ones of the recesses and barriers, and aninsulating plate connecting the adjacent radially projecting ends of onepair of barriers to conceal the space between that pair of barriers, andthereby between the sections at that barrier.

12. In a fused plug, a pair of spaced end sections, each containing afuse clip, a fuse connecting and supported in said clips, cableconnections means on one of said sections and plug contacts on theother, and means comprising elongated rods removably positioned in thesections and connecting them for maintaining them in assembly, the rodsbeing insulated from the space between the sections by tubes of rigid,form-sustaining insulation whose ends engage the sections to separatethem. Y

13. In a fused plug having an end section, plug contacts, and anapertured, rotatable, fuse-concealing shell, means on the end sectionfor preventing rotation of the shell when the plug contacts are inengagement with cooperating contacts, the means also preventing the plugcontacts from being engaged With cooperating contacts While the shell isnot in fuse 'concealing position, the means also serving to ground theplug.'

14. In a fused plug having an end section provided with plug contactsand an apertured, rotatable, fuse-concealing shell, means on the endsection for preventing rotation of the shell when'the plug contacts arein engagement with cooperating contacts the means also preventing theplug contacts from being engaged with cooperating contacts while theshell is not in fuse concealing posi# tion, the means also serving toground the plug automatically, before, during the time that and shortlyafter, the plug contacts are engaged with their cooperating contacts.

15. In a fused plug, spaced end sections of insulation havingperipherally accessible fuse containing recesses separated by radiallyextending barrier walls of insulation, a. rotatable insulating shellsurrounding said end sections and having an aperture adapted to beregistered withselected ones of the recesses and barriers, and aninsulating plate connecting the adjacent radially projecting ends of onepair of barriers to conceal the space between that pair of barriers, andthereby between the sections at that barrier, the plate and the barrierends when combined being of a greater arcuate length than that of theshell apertures.

16. In a fused plug, spaced end sections of insulation havingperipherally accessible fuse I containing recesses separated by radiallyextending barrier walls of insulation, a rotatable insulating shellsurrounding said end sections and having an aperture adapted to beregistered with selected ones of the recesses and barriers, and aninsulating plate connecting the adjacent radially projecting ends of onepair of barriers to conceal the space between that pair of barriers andthereby between the sections at that barrier, and means on the plug fornormally insuring the registry of the shell aperture with the plate.

17. ln a fused plug, spaced end sections of insulation havingperipherally accessible fuse containing recesses separated by radiallyeX- tending barrier walls of insulation, a rotatable insulating shellsurrounding said end sections and having an aperture adapted to beregistered with selected ones of the recesses and barriers, and aninsulating plate connecting thc adjacent radially projecting ends of onepair of barriers to conceal the space between that pair of barriers andthereby between the sect-ions at that barrier, and means on the plug fornormally insuring the registry of the shell aperture with the plate andfor preventing movement of the shell from such registered position, whenthe plug is live.

18. In a fused plug having a shell and fuses therewithin, means formounting the plug on and connecting it to a current distribution system,said shell being mounted so as not to be movable to fuse exposingposition when the plug is in connection with said system, said shell,when in fuse exposing position, further preventing mounting said plug onand connecting it to said shell.

In testimony whereof I sign this specifica-

